Electronic Expansion Valve Shaft Coupling for Flexible Rotor Motion
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Solution Overview
Problem
Conventional electronic expansion valves face issues with magnetic rotor flexibility due to axial forces, friction, and manufacturing accuracy, leading to bulkiness, noise, and reliability problems.
Innovation Solution
The electronic expansion valve design features a magnetic rotor surrounded by an output shaft that is slidably connected axially and drivably connected circumferentially to the screw rod, allowing the rotor to rotate freely without axial forces, along with a nut and spring rail arrangement that enhances stability and miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the magnetic rotor and screw rod are fixedly connected together by injection molding, then the structure is simplified and manufacturing is easier, but the magnetic rotor subjects to axial force transmitted from the valve needle, causing large friction resistance, deterioration in flexibility, and tendency to be jammed
Solution Approach 1:
The magnetic rotor assembly is segmented into two independent parts: the magnetic rotor itself and the screw rod. They are connected through a coupling mechanism rather than fixed injection molding, allowing the magnetic rotor to rotate independently without axial force transmission, thus maintaining flexibility while enabling easy manufacturing of separate components
Solution Approach 2:
A coupling mechanism acts as an intermediary between the magnetic rotor and screw rod. This intermediary transmits rotational motion from the magnetic rotor to the screw rod while preventing axial force transmission, resolving the contradiction between manufacturing simplicity and operational reliability
2Device complexity
If the stop rod is integrally formed with the magnetic rotor by injection molding, then the assembly process is simplified, but magnetic powder on the magnetic rotor easily drops off during stopping movement and the matching margin between the stop rod and slip ring is small
Solution Approach 1:
The stop rod is separated from the magnetic rotor as an independent component rather than being integrally formed. This segmentation allows the magnetic rotor to be manufactured separately with proper magnetic powder embedding, while the stop rod can be independently positioned and adjusted, preventing magnetic powder drop-off and ensuring adequate matching margin with the slip ring
Solution Approach 2:
The stop rod function is extracted from the magnetic rotor structure. By taking out the stop rod as a separate component, the magnetic rotor's integrity is preserved, preventing magnetic powder loss, while the stop rod can be independently optimized for its positioning function with adequate clearance to the slip ring
3Ease of manufacture
If the slip ring and spring rail are mounted at the cylindrical portion protruding from the valve seat formed by stretching process, then the manufacturing process is simplified, but it is very difficult to guarantee the coaxiality of the cylindrical portion
Solution Approach 1:
A dedicated mounting structure acts as an intermediary between the valve seat and the slip ring/spring rail assembly. This intermediary provides precise coaxial positioning features that are not dependent on the stretching process of the valve seat, allowing the slip ring and spring rail to be mounted with guaranteed coaxiality while maintaining manufacturing simplicity through modular assembly
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design improves the flexibility and stability of the magnetic rotor, reduces noise, and simplifies assembly, while ensuring high coaxiality and reliability, resulting in a more efficient and compact electronic expansion valve.
Implementation Method 1
a magnetic rotor member is driven by a coil to rotate
Implementation Method 2
the output shaft is slidably connected to the screw rod in an axial direction
Data Source
AI summary
Embodiments of the invention provide an electronic expansion valve, including a magnetic rotor and a screw rod, and further including an output shaft. The magnetic rotor is surroundingly provided on the output shaft, and the output shaft is slidably connected to the screw rod in an axial direction and drivably connected to the screw rod in a circumferential direction. Since the output shaft is slidably connected to the screw rod in an axial direction and drivably connected to the screw rod in a circumferential direction, the magnetic rotor does not subject to an axial force transmitted by the screw rod and rotates flexibly.